A wide variety of electronic devices include storage subsystems. One type of storage subsystem providing significant storage capacity utilizes a plurality of redundant array of inexpensive disks which is referred to as a RAID. RAID storage subsystems include a controller that performs significant management functions to improve reliability and performance. The controller has complex firmware containing stored programmed instructions for performing RAID storage management processes.
When a host system attempts to access the storage subsystem during a reboot, the host system often experiences service disruption. One traditional approach to a disruption is to direct the storage subsystem to respond with a ‘Device Not Ready’ indication to the host system. This approach prevents the host system from accessing the storage subsystem during and upgrade and reboot. Some host systems are equipped with high-availability feature sets that react to persistent ‘Device Not Ready’ indications by attempting to activate a redundant ‘fail-over’ path to the storage subsystem that activates an alternate storage controller. While full access to the storage subsystem can be achieved in this manner, it is definitely not transparent and is a burden on resources.